气体激光器中的类透镜效应分析

本文讨论了类负透镜介质一般曲面镜光学谐振腔,并用来分析气体激光器中的热透镜效应。对平凹腔连续波二氧化碳激光器进行了模式分析。结果表明,热透镜效应对输出功率和频率特性影响相当大,对基模输出激光器的影响最为突出。最后,简单地讨论了离子气体激光器和某些其它激光器中的可能热透镜效应。     

棒状钕玻璃热容激光器热透镜自平衡补偿方法分析

针对热容激光器的热透镜效应,给出了棒状钕玻璃热容激光器的热透镜公式表达式。理论上分析了热透镜焦距自平衡补偿方法的基本原理。在考虑了棒状钕玻璃热容激光器的具体特性的基础上,设计了一种简单的热透镜焦距自平衡补偿方法,使光抽运钕玻璃热容激光器在热透镜焦距变化情况下,可以使激光输出光斑大小稳定。为了解棒状热容激光器热透镜焦距的影响,利用自研的光栅型曲率传感器测量了热容激光器总的热透镜等效焦距的大小,结果表明热传导在抽运光发射完20 s左右后才建立热平衡产生了明显的热透镜效应; 随着抽运脉冲个数的增加,热透镜效应随之变大。     

激光热透镜效应及其等效焦距测量实验设计

基于共轴双光束干涉法设计了激光热透镜效应及其等效焦距测量装置.使用厚度约为200μm的薄酱油层样品作为观察热透镜效应的介质,将其置于半导体激光器的汇聚点上,可以在光屏上观察到同心衍射圆环,定性演示激光热透镜效应,并对热透镜的等效焦距进行定量测量.实验结果显示:薄酱油层在半导体激光照射下产生的热透镜效应可等效为凹透镜;基于共轴双光束法的热透镜等效焦距测量较为准确,利用Origin软件对8组实验数据进行线性拟合,相关系数为0.997.     

大口径铜蒸气激光器的动力学分析

通过建立调整大口径铜蒸气激光器的动力学模拟过程中的有关动力学参数,得到一适用于不同输出功率的大口径铜蒸气激光器动力学模型.在此基础上对大口径铜蒸气激光器的径向动力学参量进行了计算,包括激励电场和亚稳态铜粒子密度等动力学参量的径向分布.给出了大口径铜蒸气激光器的径向电子温度及发光强度分布.尔后得到在不同充电电压及缓冲气压条件下铜蒸气激光器的输出功率,此程序对Φ=65cm的大口径铜蒸气激光器的计算结果与实验符合得相当好. 关键词：     

固体激光棒热透镜焦距的测量

固体激光棒中的热透镜效应对激光器的性能有很大的影响.在固体激光器的热稳腔的设计中也需要知道激光棒的热透镜焦距的数值,因此测量激光棒的热透镜焦距是必要的和有意义的.我们采用类似于文献[1]中的方法,测量了三种常用的固体激光棒在泵浦期间和泵浦后,各个时刻的热透镜焦距的数值.在单脉冲泵浦期间,红宝石、Nd:YAG和钕玻璃三种激光棒的热透镜焦距均为负值. 测量热透镜焦距的原理如图1所示.设He-Ne探测激光束的束腰半径为ω0,束腰和光阑离热透镜的距离分别为d1和d2。ωn和ωm分别为存在热透镜(例如负透镜)和无热透镜时探测激光束到达光…     

高功率高重复频率全固态激光器热透镜效应补偿与分析

将kHz高功率固体激光器增益介质当作厚透镜处理,建立了热透镜效应分析的理论模型,使用矩阵的方法对等效热透镜腔进行分析.对增益介质抽运均匀性进行了改善,通过分析模拟计算结果,设计了混合非稳腔结构,选择了最佳凸面镜曲率半径对热透镜效应进行补偿.试验结果表明,补偿效果明显,kHz高功率全固态激光器的光束发散角优于1.3 mrad.     

铜蒸气激光器等离子体阻抗动态特性研究

给出了铜蒸气激光器放电电路各参数的表达式及取值。与铜蒸气激光器动力学模型相结合,讨论了铜蒸气激光器动力学过程中由于放电管内等离子体参数的变化引起等离子体阻抗动态演变过程,并与采用固定等离子体参数的等离子体阻抗进行了比较。     

LD端面泵浦Nd∶YAG激光器中的热透镜焦距

采用热透镜焦距的理论计算与实验测量相比较的研究方法，得到一种端泵固体激光器出激光时的在线测量方法.通过建立热透镜等效腔模型以及腔型分析求解得出腔内光束束腰半径,用刀口法测出DPL腔外的远场发散角,根据发散角与透镜变换前后的束腰关系，得出LD端面泵浦Nd∶YAG激光器中的热透镜焦距.结果表明,通过上述方法所得结果与理论计算的热透镜焦距吻合,证实此方法准确、可行.     

铜蒸气激光器等离子体阻抗动态特性研究

 给出了铜蒸气激光器放电电路各参数的表达式及取值。与铜蒸气激光器动力学模型相结合,讨论了铜蒸气激光器动力学过程中由于放电管内等离子体参数的变化引起等离子体阻抗动态演变过程,并与采用固定等离子体参数的等离子体阻抗进行了比较。     

铜蒸气激光泵浦的高效脉冲若丹明6G染料激光器(英文)

本文给出了铜蒸气激光泵浦的脉冲染料激光器性能的理论预测.根据这个理论,设计了一台用铜蒸气激光泵浦的、具有纵向泵浦结构和喷流的高功率高效率若丹明6G染料激光器.对若丹明6G染料,得到了0.86W的平均输出功率,效率为31%.     

利用准直管法测凹透镜的焦距

介绍了利用准直管精确测量凹透镜焦距的方法，该方法借助一个焦距较长的凸透镜与被测凹透镜组成无焦系统，可以使准直管出射光束的张角发生改变；用一辅助凸透镜与一测微目镜进行平行光束的会聚，测出准直管玻罗板线对在辅助凸透镜焦平面上所成像的大小；经过相应计算可得到被测凹透镜的焦距。     

Dependence of curvature type of thermal lensing on number of bounces in a zigzag slab laser: numerical modeling

The curvature type of the thermal lens generated in a zigzag slab laser is numerically analysed. It is found that the curvature type of the thermal lens varies alternatively between the convex and the concave lenses with the number of bounces of light within the slab, which can be well explained by the trace of the zigzag propagation. In addition, we conclude that the beamlet with a larger number of bounces experiences weaker thermal lensing but more serious wavefront deformation due to the large side lobe portion in the curve of optical path difference.     

High beam quality in a HyBrID copper laser operating with an unstable resonator made of a concave mirror and a plano-convex BK7 lens

This paper presents a very simple unstable resonator, made of a concave mirror (total reflector) and a bare plane–convex BK7 lens working as a convex coupling mirror, which is quite efficient for HyBrID copper laser. In addition to a good quality factor (M²=4.9), experimental results showed that it is possible to control the laser output power by introducing a variable aperture iris inside the cavity, close to the coupling lens, without spoiling beam quality. A rough theoretical model helped to explain these results as a combined effect of unstable resonator plus radial gain distribution.     

热透镜对铜蒸气激光振荡器与放大器输出光的影响

用几何光学传输矩阵方法和讨论了热透镜对铜蒸气激光非稳腔振荡器和放大器输出特性的影响，获得了与实验相符的计算结果，并提出了在振荡－放大链内热透效应的补偿方法。     

Movable and Focus-Tunable Lens Based on Electrically Controllable Liquid: A Lattice Boltzmann Study

Adjusting the focal length by changing the liquid interface of the liquid lens has become a potential method. In this paper, the lattice-Boltzmann-electrodynamic (LB-ED) method is used to numerically investigate the zooming process of a movable and focus-tunable electrowetting-on-dielectrics (EWOD) liquid lens by combining the LBM chemical potential model and the electrodynamic model. The LB method is used to solve the Navier–Stokes equation, and the Poisson–Boltzmann (PB) equation is introduced to solve the electric field distribution. The experimental results are consistent with the theoretical results of the Lippmann–Young equation. Through the simulation of a liquid lens zoom driven by EWOD, it is found that the lens changes from a convex lens to a concave lens with the voltage increases. The focal length change rate in the convex lens stage gradually increases with voltage. In the concave lens stage, the focal length change rate is opposite to that in the convex lens stage. During the zooming process, the low-viscosity liquid exhibits oscillation, and the high-viscosity liquid appears as overdamping. Additionally, methods were proposed to accelerate lens stabilization at low and high viscosities, achieving speed improvements of about 30% and 50%, respectively. Simulations of lens motion at different viscosities demonstrate that higher-viscosity liquids require higher voltages to achieve the same movement speed.     

Liquid Pressure Varifocus Lens

A liquid pressure varifocus lens that consists of a thin polymer film and liquid is described. The lens can be continuously changed from a concave to a convex shape by driving the liquid pressure in the lens. The dynamic range of the focal length of the convex lens is from 50 to 250 mm. A beam spot verifies the variable focal function on a photographic film exposed by a He-Ne laser. In addition, the application of the laser for processing is demonstrated to manufacture Fe compressed powder sheets by normal pulse YAG laser. Its melting marks along a focus change are formed with a minimum width of 0.1 mm.     

基于猫眼腔镜损耗调节的激光横模演示系统

提出一种基于猫眼腔镜损耗调节的新型激光横模演示系统。采用半外腔He-Ne激光器,利用由分立的可进行五维微调的凸透镜和凹面镜组成的猫眼逆向器构成损耗可调激光谐振腔,通过调节猫眼逆向器改变激光谐振腔的损耗比，实现改变激光横模状态的作用。利用CCD进行图像采集，计算机实现图像存储，从而得到20多种结构清晰的高阶横模花样图片。     

Error compensation in reflection type centering error testing

The error compensation for an error caused from unwanted surfaces when using single autocollimator reflection type centering error testing. And compare the result with commercial equipment like OptiCentric built by TRIOPTICS GmbH using a concave lens and a convex lens.     

Experiments on New Arrangements of Convex and Concave Corrugated Tubes through a Double-pipe Heat Exchanger

The main scope of this article paper is to experimentally clarify the effects of outer-tube and inner-tube corrugations on thermal and frictional characteristics in a horizontal double-pipe heat exchanger. Nusselt number, friction factor, and thermal performance factor are evaluated for new various arrangements of convex and concave corrugated tubes. Smooth tubes were corrugated by means of a special machine. Findings indicate that the arrangement type of corrugated tubes has a significant effect on the mentioned parameters. The best performance was obtained for a heat exchanger made of a concave corrugated outer tube and a convex corrugated inner tube.     

高斯光束经复合光学系统的聚焦特性

讨论了高斯光束经由凹透镜,子系统和凸透镜构成的复合光学系统的聚焦特性,利用矩阵光学方法,推导出了高斯光束经复合光学系统聚焦后束腰宽度和像距的计算公式。计算例表明,选择适当参数的复合光学系统,既可以获得较小的束腰宽度,又可以获得较长的像距。